1. Field of the Invention
This invention relates to an engine generator set which serves as a power source for supplying electric power to road facilities, such as traffic signals, and outdoor work facilities, and as one for emergency purposes during failure of mains power.
2. Prior Art
Conventionally, engine-driven generators (hereinafter referred to as "engine generators") are generally employed as a generator set of this kind. Such engine generators are used for supplying electric power to road facilities, such as traffic signals and outdoor work facilities. They are likely to be constantly exposed to weather, sunlight, dust, etc. Therefore, the engine generators are required to be constructed so as to endure service environmental conditions such as weather over a long term.
Further, an engine generator is often used as a power source for night work operations, and therefore are required to have reduced noise.
To comply with the above-mentioned requirements, the present assignee proposed "SOUNDPROOF ENGINE-DRIVEN WORKING MACHINE" (Japanese Patent Publication (Kokoku) No. 2-5897). As shown in FIGS. 8 and 9, the proposed soundproof engine-driven working machine is comprised of a soundproof casing 1, an engine 31 received in a lower portion of the soundproof casing 1, and a generator 41 received in an upper potion of the same and driven by the engine 31.
The soundproof casing 1 includes upper doors 11, 13 and lower doors 12, 14 provided respectively on front and rear sides thereof, and wire mesh doors 15, 17 provided respectively inside the lower doors 12, 14. When the engine-driven working machine is not operating, the upper and lower doors 11 to 14 are closed, whereas when it is operating, as shown in FIGS. 9 and 10, the lower doors 12, 14 are opened for ventilation, i.e. for introducing intake air to be supplied to the engine and discharging exhaust gases emitted from the engine, as well as for cooling the inside of the soundproof casing 1. This soundproof engine-driven working machine can endure severe environmental conditions for a long term by holding the upper and lower doors 11 to 14 closed when it is not operating.
However, since the proposed soundproof engine-driven working machine is operated with the lower doors 12, 14 held open for introducing intake air from the outside and discharging exhaust gases to the same as well as for cooling the inside of the soundproof casing 1, the lower doors 12, 14 have to be opened first by hand before putting the machine into operation. Therefore, it is practically impossible to automatically start the machine or operate the same by remote control when the power fails. Especially when the engine-driven working machine is installed at a remote place, one has to waste for a considerable time period before the machine is started.
Further, when electric power is supplied to a working site far from the location of the soundproof engine-driven working machine, it is required to lay a cable over a long distance. In such a case, it takes much labor and time in handling the cable, and a significant voltage drop across the long cable results in a decrease in the maximum power available from the engine-driven working machine.
In view of these problems, the present assignee has already proposed a generator set in Japanese Patent Application No. 7-94836, which is constructed such that a portable engine generator can be operated not only in a state accommodated or received within a permanent soundproof housing thereof, but also in a state separate from the housing as a single unit.
However, the generator set or the engine-driven working machine discussed above is often installed in a limited space, e.g. between roadside trees or flower beds along a sidewalk adjacent to a roadway so as to keep it out of the way of passersby. This makes it difficult to secure a sufficient space for the operation of taking the portable engine generator out of the soundproof casing when it has to be operated outside the housing.